Self-crosslinking hyaluronic acid hydrogel as an enteroprotective agent for the treatment of inflammatory bowel disease

The pathological changes in inflammatory bowel disease (IBD) include the disruption of intestinal barrier function and the infiltration of pathogenic microbes. The application of an artificial protective barrier at the site of inflammation can prevent bacterial infiltration, promote epithelial cell migration, and accelerate wound healing. In this study, dopamine-modified hyaluronic acid (HA-DA) was developed as a bioadhesive self-cross-linkable hydrogel, which acted as an enteroprotective agent to promote the healing of inflamed intestinal tissue. The adhesion strength HA-DA to mouse colon was 3.81-fold higher than HA. Moreover, HA-DA promoted Caco-2 cell proliferation and migration as well as had a strong physical barrier effect after gelation. After oral administration, the HA-DA reduced weight loss and attenuated impaired goblet cell function in mice with dextran sodium sulfate-induced IBD. In addition, HA-DA promoted restoration of the epithelial barrier by the upregulation of tight junction proteins. The results reported herein substantiated that self-cross-linkable hydrogel-based enteroprotective agents are a promising approach for the treatment of IBD.

A Universal Strategy to Construct High-Performance Homo- and Heterogeneous Microgel Assembly Bioinks

Three dimensional (3D) extrusion bioprinting aims to replicate the complex architectures and functions of natural tissues and organs. However, the conventional hydrogel and new-emerging microgel bioinks are both difficult in achieving simultaneously high shape-fidelity and good maintenance of cell viability/function, leading to limited amount of qualified hydrogel/microgel bioinks. Herein, a universal strategy is reported to construct high-performance microgel assembly (MA) bioinks by using epigallocatechin gallate-modified hyaluronic acid (HA-EGCG) as coating agent and phenylboronic acid grafted hyaluronic acid (HA-PBA) as assembling agent. HA-EGCG can spontaneously form uniform coating on the microgel surface via mussel-inspired chemistry, while HA-PBA quickly forms dynamic phenylborate bonds with HA-EGCG, conferring the as-prepared MA bioinks with excellent rheological properties, self-healing, and tissue-adhesion. More importantly, this strategy is applicable to various microgel materials, enabling the preparation of homo- and heterogeneous MA (homo-MA and hetero-MA) bioinks and the hierarchical printing of complicated structures with high fidelity by integration of different microgels containing multiple materials/cells in spatial and compositional levels. It further demonstrates the printing of breast cancer organoid in vitro using homo-MA and hetero-MA bioinks and its preliminary application for drug testing. This universal strategy offers a new solution to construct high-performance bioinks for extrusion bioprinting.

Employing Noble Metal-Porphyrins to Engineer Robust and Highly Active Single-Atom Nanozymes for Targeted Catalytic Therapy in Nasopharyngeal Carcinoma

Single-atom nanozymes (SANzymes) emerge as promising alternatives to conventional enzymes. However, chemical instability limits their application. Here, a systematic synthesis of highly active and stable SANzymes is presented by leveraging noble metal-porphyrins. Four noble metal-porphyrins are successfully synthesized to mimic the active site of natural peroxidases through atomic metal-N coordination anchored to the porphyrin center. These noble metal-porphyrins are integrated into a stable and biocompatible Zr-based metal-organic framework (MxP, x denoting Ir, Ru, Pt, and Pd). Among these, MIrP demonstrates superior peroxidase-like activity (685.61 U mg-1 ), catalytic efficiency, and selectivity compared to horseradish peroxidase (267.71 U mg-1 ). Mechanistic investigations unveil heightened catalytic activity of MIrP arises from its robust H2 O2 adsorption capacity, unique rate-determining step, and low energy threshold. Crucially, MIrP exhibits remarkable chemical stability under both room temperature and high H2 O2 concentrations. Further, through modification with (-)-Epigallocatechin-3-Gallate, a natural ligand for Epstein-Barr virus (EBV)-encoded latent membrane protein 1, targeted SANzyme (MIrPHE) tailored for EBV-associated nasopharyngeal carcinoma is engineered. This study not only presents an innovative strategy for augmenting the catalytic activity and chemical stability of SANzymes but also highlights the substantial potential of MIrP as a potent nanomedicine for targeted catalytic tumor therapy.

Engineering MMP-2 Activated Nanoparticles Carrying B7-H3 Bispecific Antibodies for Ferroptosis-Enhanced Glioblastoma Immunotherapy

Administration of bispecific antibodies (biAbs) in tumor therapy is limited by their short half-life and off-target toxicity. Optimized strategies or targets are needed to overcome these barriers. B7-H3 (CD276), a member of the B7 superfamily, is associated with poor survival in glioblastoma (GBM) patients. Moreover, a dimer of EGCG (dEGCG) synthesized in this work enhanced the IFN-γ-induced ferroptosis of tumor cells in vitro and in vivo. Herein, we prepared recombinant anti-B7-H3×CD3 biAbs and constructed MMP-2-sensitive S-biAb/dEGCG@NPs to offer a combination treatment strategy for efficient and systemic GBM elimination. Given their GBM targeted delivery and tumor microenvironment responsiveness, S-biAb/dEGCG@NPs displayed enhanced intracranial accumulation, 4.1-, 9.5-, and 12.3-fold higher than that of biAb/dEGCG@NPs, biAb/dEGCG complexes, and free biAbs, respectively. Furthermore, 50% of GBM-bearing mice in the S-biAb/dEGCG@NP group survived longer than 56 days. Overall, S-biAb/dEGCG@NPs can induce GBM elimination by boosting the ferroptosis effect and enhancing immune checkpoint blockade (ICB) immunotherapy and may be successful antibody nanocarriers for enhanced cancer therapy.

Multifunctional Microgel-Based Cream Hydrogels for Postoperative Abdominal Adhesion Prevention

Postoperative abdominal adhesions are a common problem after surgery and can produce serious complications. Current antiadhesive strategies focus mostly on physical barriers and are unsatisfactory and inefficient. In this study, we designed and synthesized advanced injectable cream-like hydrogels with multiple functionalities, including rapid gelation, self-healing, antioxidation, anti-inflammation, and anti-cell adhesion. The multifunctional hydrogels were facilely formed by the conjugation reaction of epigallocatechin-3-gallate (EGCG) and hyaluronic acid (HA)-based microgels and poly(vinyl alcohol) (PVA) based on the dynamic boronic ester bond. The physicochemical properties of the hydrogels including antioxidative and anti-inflammatory activities were systematically characterized. A mouse cecum-abdominal wall adhesion model was implemented to investigate the efficacy of our microgel-based hydrogels in preventing postoperative abdominal adhesions. The hydrogels, with a high molecular weight HA, significantly decreased the inflammation, oxidative stress, and fibrosis and reduced the abdominal adhesion formation, compared to the commercial Seprafilm group or Injury-only group. Label-free quantitative proteomics analysis demonstrated that S100A8 and S100A9 expressions were associated with adhesion formation; the microgel-containing hydrogels inhibited these expressions. The microgel-containing hydrogels with multifunctionality decreased the formation of postoperative intra-abdominal adhesions in a murine model, demonstrating promise for clinical applications.

Green tea catechin-grafted silk fibroin hydrogels with reactive oxygen species scavenging activity for wound healing applications

BACKGROUND

Overproduction of reactive oxygen species (ROS) is known to delay wound healing by causing oxidative tissue damage and inflammation. The green tea catechin, (-)-Epigallocatechin-3-O-gallate (EGCG), has drawn a great deal of interest due to its strong ROS scavenging and anti-inflammatory activities. In this study, we developed EGCG-grafted silk fibroin hydrogels as a potential wound dressing material.

METHODS

The introduction of EGCG to water-soluble silk fibroin (SF-WS) was accomplished by the nucleophilic addition reaction between lysine residues in silk proteins and EGCG quinone at mild basic pH. The resulting SF-EGCG conjugate was co-crosslinked with tyramine-substituted SF (SF-T) via horseradish peroxidase (HRP)/H2O2 mediated enzymatic reaction to form SF-T/SF-EGCG hydrogels with series of composition ratios.

RESULTS

Interestingly, SF-T70/SF-EGCG30 hydrogels exhibited rapid in situ gelation (< 30 s), similar storage modulus to human skin (≈ 1000 Pa) and superior wound healing performance over SF-T hydrogels and a commercial DuoDERM® gel dressings in a rat model of full thickness skin defect.

CONCLUSION

This study will provide useful insights into a rational design of ROS scavenging biomaterials for wound healing applications.

Designing functional hyaluronic acid-based hydrogels for cartilage tissue engineering

Damage to cartilage tissues is often difficult to repair owing to chronic inflammation and a lack of bioactive factors. Therefore, developing bioactive materials, such as hydrogels acting as extracellular matrix mimics, that can inhibit the inflammatory microenvironment and promote cartilage repair is crucial. Hyaluronic acid, which exists in cartilage and synovial fluid, has been extensively investigated for cartilage tissue engineering because of its promotion of cell adhesion and proliferation, regulation of inflammation, and enhancement of cartilage regeneration. However, hyaluronic acid-based hydrogels have poor degradation rates and unfavorable mechanical properties, limiting their application in cartilage tissue engineering. Recently, various multifunctional hyaluronic acid-based hydrogels, including alkenyl, aldehyde, thiolated, phenolized, hydrazide, and host–guest group-modified hydrogels, have been extensively studied for use in cartilage tissue engineering. In this review, we summarize the recent progress in the multifunctional design of hyaluronic acid-based hydrogels and their application in cartilage tissue engineering. Moreover, we outline the future research prospects and directions in cartilage tissue regeneration. This would provide theoretical guidance for developing hyaluronic acid-based hydrogels with specific properties to satisfy the requirements of cartilage tissue repair.

Bio-functional hydrogel with antibacterial and anti-inflammatory dual properties to combat with burn wound infection

Burn infection delays wound healing and increases the burn patient mortality. Consequently, a new dressing with antibacterial and anti-inflammatory dual properties is urgently required for wound healing. In this study, we propose a combination of methacrylate gelatin (GelMA) hydrogel system with silver nanoparticles embed in γ-cyclodextrin metal-organic frameworks (Ag@MOF) and hyaluronic acid-epigallocatechin gallate (HA-E) for the burn wound infection treatment. Ag@MOF is used as an antibacterial agent and epigallocatechin gallate (EGCG) has exhibited biological properties of anti-inflammation and antibacterial. The GelMA/HA-E/Ag@MOF hydrogel enjoys suitable physical properties and sustained release of Ag⁺. Meanwhile, the hydrogel has excellent biocompatibility and could promote macrophage polarization from M1 to M2. In vivo wound healing evaluations further demonstrate that the GelMA/HA-E/Ag@MOF hydrogel reduces the number of the bacterium efficiently, accelerates wound healing, promotes early angiogenesis, and regulates immune reaction. A further evaluation indicates that the noncanonical Wnt signal pathway is significantly activated in the GelMA/HA-E/Ag@MOF hydrogel treated group. In conclusion, the GelMA/HA-E/Ag@MOF hydrogel could serve as a promising multifunctional dressing for the burn wound healing.

A multi-target theranostic nano-composite against Alzheimer's disease fabricated by conjugating carbon dots and triple-functionalized human serum albumin

The complex pathogenesis of Alzheimer's disease (AD) involves the aggregation and accumulation of amyloid β-protein (Aβ) as well as elevated levels of reactive oxygen species (ROS), which requires the development of comprehensive diagnostic and therapeutic interventions. In this work, a multifunctional theranostic nano-composite (HSA-BFP@CDs) is constructed by conjugating triple-functionalized human serum albumin (HSA-BFP) as a theranostic agent targeting Aβ and carbon dots (CDs) as an ROS scavenger. HSA-BFP@CDs exhibits a fluorescence "off-on" effect at 700 nm upon interaction with Aβ aggregates, showing the capability for detection of Aβ plaques and potential for early diagnosis of AD. Besides, HSA-BFP@CDs effectively inhibits the aggregation of Aβ, increasing the viability of Aβ-treated cells from 74% to over 95% at 100 µg/mL. Moreover, multiple ROS, including hydroxyl radicals, superoxide radicals, hydrogen peroxide, and Aβ-Cu²⁺-induced-ROS, can be scavenged by HSA-BFP@CDs, thus resulting in the mitigation of cellular oxidative damages. Experiments with the AD model of Caenorhabditis elegans further demonstrate the multifunctionality of HSA-BFP@CDs in imaging amyloid plaques, reducing Aβ deposition, and relieving oxidative stress in vivo, showing the prospect for Aβ- and ROS-targeted AD diagnosis and treatment. This work provided new insight into the design of protein-carbon dots conjugate and the development of multi-target therapy of AD. STATEMENT OF SIGNIFICANCE: Alzheimer's disease (AD) is the most common form of dementia, which currently affects over 55 million people worldwide. Due to the complex pathogenesis of AD involving amyloid β-protein (Aβ) aggregation as well as elevated levels of reactive oxygen species (ROS), it is highly desired to develop comprehensive diagnostic and therapeutic interventions. In this paper, we fabricated a multifunctional theranostic nano-composite (HSA-BFP@CDs) via the conjugation of triple-functionalized human serum albumin (HSA-BFP) and carbon dots (CDs). The multifunctionality of HSA-BFP@CDs for efficient detection of Aβ aggregates and inhibition of Aβ aggregation as well as scavenging of ROS was demonstrated, demonstrating the potential of the protein-carbon dots conjugate for the multi-target therapy of AD.

Epigallocatechin 3-gallate: From green tea to cancer therapeutics

Epigallocatechin 3-gallate (EGCG) possesses various biological functions, including anti-cancer and anti-inflammatory properties. EGCG is an abundant polyphenolic component originating from green tea extract that has exhibited versatile bioactivities in combating several cancers. This review highlights the pharmacological features of EGCG and its therapeutic implications in cancer and other metabolic diseases. It modulates numerous signaling pathways, regulating cells' undesired survival and proliferation, thus imparting strong tumor chemopreventive and therapeutic effects. EGCG initiates cell death through the intrinsic pathway and causes inhibition of EGFR, STAT3, and ERK pathways in several cancers. EGCG alters and inhibits ERK1/2, NF-κB, and Akt-mediated signaling, altering the Bcl-2 family proteins ratio and activating caspases in tumor cells. This review focuses on anti-cancer, anti-oxidant, anti-inflammatory, anti-angiogenesis, and apoptotic effects of EGCG. We further highlighted the potential of EGCG in different types of cancer, emphasizing clinical trials formulations that further improve our understanding of the therapeutic management of cancer and inflammatory diseases.

A Tumor-Specific Ferric-Coordinated Epigallocatechin-3-gallate cascade nanoreactor for glioblastoma therapy

Introduction

Numerous options for treatment of glioblastoma have been explored; however, single-drug therapies and poor targeting have failed to provide effective drugs. Chemotherapy has significant antitumor effect, but the efficacy of single-drug therapies in the clinic is limited over a long period of time. Thus, novel therapeutic approaches are necessary to address these critical issues.

Objectives

The present study, we investigated a tumor-specific metal-tea polyphenol-based cascade nanoreactor for chemodynamic therapy-enhanced chemotherapy.

Methods

HA-EGCG was synthesized for the first time by introducing epigallocatechin-3-gallate (EGCG) into the skeleton of hyaluronic acid (HA) with reducible disulfide bonds. A rapid and green method was developed to fabricate the metal-tea polyphenol networks (MTP) with an HA-EGCG coating (DOX@MTP/HA-EGCG) based on Fe3+ and EGCG for targeted delivery of doxorubicin hydrochloride (DOX). GL261 cells were used to evaluate the antitumor efficacy of the DOX@MTP/HA-EGCG nanoreactor in vitro and in vivo.

Results

DOX@MTP/HA-EGCG nanoreactors were able to disassemble, resulting in escape of their components from lysosomes and precise release of DOX, Fe3+, and EGCG in the tumor cells. HA-EGCG depleted glutathione to amplify oxidative stress and enhance chemodynamic therapy. The results of in vivo experiments suggested that DOX@MTP/HA-EGCG specifically accumulates at the CD44-overexpressing GL261 tumor sites and that sustained release of DOX and Fe3+ induced a distinct therapeutic outcome.

Conclusions

The findings suggested the developed nanoreactor has promising potential as a future GL261 glioblastoma therapy.

Collagen- and hyaluronic acid-based hydrogels and their biomedical applications

Hydrogels have been widely investigated in biomedical fields due to their similar physical and biochemical properties to the extracellular matrix (ECM). Collagen and hyaluronic acid (HA) are the main components of the ECM in many tissues. As a result, hydrogels prepared from collagen and HA hold inherent advantages in mimicking the structure and function of the native ECM. Numerous studies have focused on the development of collagen and HA hydrogels and their biomedical applications. In this extensive review, we provide a summary and analysis of the sources, features, and modifications of collagen and HA. Specifically, we highlight the fabrication, properties, and potential biomedical applications as well as promising commercialization of hydrogels based on these two natural polymers.

Hyaluronic acid-green tea catechin conjugates as a potential therapeutic agent for rheumatoid arthritis

Fibroblast-like synoviocytes are a key effector cell type involved in the pathogenesis of rheumatoid arthritis. The major green tea catechin, epigallocatechin-3-O-gallate (EGCG), has attracted significant interest for rheumatoid arthritis therapy because of its ability to suppress the proliferation and interleukin-6 secretion of synoviocytes. However, therapeutic efficacy of EGCG has been limited by a lack of target cell specificity. Herein we report hyaluronic acid-EGCG (HA-EGCG) conjugates as an anti-arthritic agent that is capable of targeting fibroblast-like synoviocytes via HA-CD44 interactions. These conjugates exhibited superior anti-proliferative and anti-inflammatory activities compared with EGCG under simulated physiological conditions. Near-infrared fluorescence imaging revealed preferential accumulation of the conjugates at inflamed joints in a collagen-induced arthritis rat model, and their anti-arthritic efficacy was investigated by measuring a change in the edema and histopathological scores. Our findings suggest the potential of HA-EGCG conjugates as an anti-arthritic agent for the treatment of rheumatoid arthritis.

Biocompatible, Antioxidant Nanoparticles Prepared from Natural Renewable Tea Polyphenols and Human Hair Keratins for Cell Protection and Anti-inflammation

Excessive reactive oxygen species (ROS) can cause oxidative stress of tissues and adversely influence homeostasis of the body. Epigallocatechin gallate (EGCG) with an antioxidative effect can effectively eliminate the ROS, but an evident weakness associated with it is the relatively poor cytocompatibility. Combining with other biomacromolecules such as human hair keratin (KE) and using nanotechnology to prepare nanoparticles can improve this situation. By covalent bonding, we assembled KE and EGCG into KE-EGCG nanoparticles (NANO) with size of about 50 nm and characterized them by DLS, UV, FTIR, NMR, and XPS. Free radical scavenging experiments show that antioxidant properties of the obtained NANO are superior to that of vitamin C. Cell culture experiments also show that the NANO can effectively protect the proliferation of L929 cells and HUVEC cells. In addition, we also used RAW264.7 cells to establish a H₂O₂-induced cell injury model and an lipopolysaccharide-induced cellular inflammatory model to evaluate the antioxidant and anti-inflammatory properties of NANO. The results show that the NANO can effectively prevent cells from oxidative damage and reduce inflammatory expression of the cells, indicating that the NANO have a good antioxidative and anti-inflammatory effect on cells which can be applied to many diseases related to oxidative stress.

Catechins as Model Bioactive Compounds for Biomedical Applications

Research regarding polyphenols has gained prominence over the years because of their potential as pharmacological nutrients. Most polyphenols are flavanols, commonly known as catechins, which are present in high amounts in green tea. Catechins are promising candidates in the field of biomedicine. The health benefits of catechins, notably their antioxidant effects, are related to their chemical structure and the total number of hydroxyl groups. In addition, catechins possess strong activities against several pathogens, including bacteria, viruses, parasites, and fungi. One major limitation of these compounds is low bioavailability. Catechins are poorly absorbed by intestinal barriers. Some protective mechanisms may be required to maintain or even increase the stability and bioavailability of these molecules within living organisms. Moreover, novel delivery systems, such as scaffolds, fibers, sponges, and capsules, have been proposed. This review focuses on the unique structures and bioactive properties of catechins and their role in inflammatory responses as well as provides a perspective on their use in future human health applications.

Multifunctional hydrogels for wound healing: Special focus on biomacromolecular based hydrogels

Hydrogels are widely used for wound healing applications due to their similarity to the native extracellular matrix (ECM) and ability to provide a moist environment. However, lack of multifunctionality and low mechanical properties of previously developed hydrogels may limit their ability to support skin tissue regeneration. Incorporating various biomaterials and nanostructures into the hydrogels is an emerging approach to develop multifunctional hydrogels with new functions that are beneficial for wound healing. These multifunctional hydrogels can be fabricated with a wide range of functions and properties, including antibacterial, antioxidant, bioadhesive, and appropriate mechanical properties. Two approaches can be used for development of multifunctional hydrogel-based dressings; taking the advantages of the chemical composition of biomaterials and addition of nanomaterials or nanostructures. A large number of synthetic and natural polymers, bioactive molecules, or nanomaterials have been used to obtain hydrogel-based dressings with multifunctionality for wound healing applications. In the present review paper, advances in the development of multifunctional hydrogel-based dressings for wound healing have been highlighted.

Engineering nanoparticles to locally activate T cells in the tumor microenvironment

Immunological tolerance of tumors is characterized by insufficient infiltration of cytotoxic T lymphocytes (CTLs) and immunosuppressive microenvironment of tumor. Tumor resistance to immune checkpoint inhibitors due to immunological tolerance is an ongoing challenge for current immune checkpoint blockade (ICB) therapy. Here, we report the development of tumor microenvironment-activatable anti-PDL1 antibody (αPDL1) nanoparticles for combination immunotherapy designed to overcome immunological tolerance of tumors. Combination of αPDL1 nanoparticle treatment with near-infrared (NIR) laser irradiation-triggered activation of photosensitizer indocyanine green induces the generation of reactive oxygen species, which promotes the intratumoral infiltration of CTLs and sensitizes the tumors to PDL1 blockade therapy. We showed that the combination of antibody nanoparticles and NIR laser irradiation effectively suppressed tumor growth and metastasis to the lung and lymph nodes in mouse models. The nanoplatform that uses the antibody nanoparticle alone both for immune stimulation and PDL1 inhibition could be readily adapted to other immune checkpoint inhibitors for improved ICB therapy.

Fabrication of polyphenol-incorporated anti-inflammatory hydrogel via high-affinity enzymatic crosslinking for wet tissue adhesion

Epigallocatechin gallates (EGCGs), isolated from green tea, have intrinsic properties such as anti-oxidant, anti-inflammation, and radical scavenger effects. In this study, we report a tissue adhesive and anti-inflammatory hydrogel formed by high-affinity enzymatic crosslinking of polyphenolic EGCGs. A mixture of EGCG conjugated hyaluronic acids (HA_E) and tyramine conjugated hyaluronic acids (HA_T) was reacted with tyrosinase isolated from Streptomyces avermitillis (SA_Ty) to form that displayed fast enzyme kinetic to form a crosslinked adhesive hydrogel. A 1,2,3-trihydroxyphenyl group in EGCG displayed a high affinity to SA_Ty that allowed HA_E to be quickly oxidized and crosslinked with HA_T to form HA_T and HA_E mixed hydrogel (HA_TE). We then compared the HA_TE hydrogel with commercially available tissue adhesives, such as cyanoacrylate and fibrin glue. We report that the HA_TE exhibited the highest tissue adhesiveness both in wet and dry conditions. Furthermore, HA_TE successfully closed a skin wound and displayed insignificant host tissue responses. This demonstrates that polyphenol-incorporated anti-inflammatory hydrogel may provide a robust tissue adhesive platform for clinical applications.

Controllable silicon nanostructures featuring stable fluorescence and intrinsic in vitro and in vivo anti-cancer activity

In this manuscript, we demonstrate that the in situ growth of fluorescent silicon (Si) nanomaterials is stimulated when organosilicane molecules interact with different green teas, producing multifunctional Si nanomaterials with controllable zero- (e.g., nanoparticles), two- (e.g., nanosheets), and three- (e.g., nanospheres) dimensional nanostructures. Such green tea-originated Si nanomaterials (GTSN) exhibit strong fluorescence (quantum yield: ∼19-30%) coupled with ultrahigh photostability, as well as intrinsic anti-cancer activity with high specificity (e.g., the GTSN can accurately kill various cancer cells, rather than normal cells). Taking advantage of these unique merits, we further performed systematic in vitro and in vivo experiments to interrogate the mechanism of the green tea- and GTSN-related cancer prevention. Typically, we found that the GTSN entered the cell nuclei and induced cell apoptosis/death of cancer cells. The prepared GTSN were observed in vivo to accumulate in the tumour tissues after 14-d post-injection, leading to an efficient inhibition of tumour growth. Our results open new avenues for designing novel multifunctional and side-effect-free Si nanomaterials with controllable structures.

The proper strategy to compress and protect plasmid DNA in the Pluronic L64-electropulse system for enhanced intramuscular gene delivery

Intramuscular expression of functional proteins is a promising strategy for therapeutic purposes. Previously, we developed an intramuscular gene delivery method by combining Pluronic L64 and optimized electropulse, which is among the most efficient methods to date. However, plasmid DNAs (pDNAs) in this method were not compressed, making them unstable and inefficient in vivo. We considered that a proper compression of pDNAs by an appropriate material should facilitate gene expression in this L64-electropulse system. Here, we reported our finding of such a material, Epigallocatechin gallate (EGCG), a natural compound in green teas, which could compress and protect pDNAs and significantly increase intramuscular gene expression in the L64-electropulse system. Meanwhile, we found that polyethylenimine (PEI) could also slightly improve exogenous gene expression in the optimal procedure. By analysing the characteristic differences between EGCG and PEI, we concluded that negatively charged materials with strong affinity to nucleic acids and/or other properties suitable for gene delivery, such as EGCG, are better alternatives than cationic materials (like PEI) for muscle-based gene delivery. The results revealed that a critical principle for material/pDNA complex benefitting intramuscular gene delivery/expression is to keep the complex negatively charged. This proof-of-concept study displays the breakthrough in compressing pDNAs and provides a principle and strategy to develop more efficient intramuscular gene delivery systems for therapeutic applications.

Delivery of synergistic polyphenol combinations using biopolymer-based systems: Advances in physicochemical properties, stability and bioavailability

When consumed at sufficiently high levels, polyphenols may provide health benefits, which is linked to their antidiabetic, antiinflamatory, antimicrobial, antioxidant, antitumor, and hypolipidemic properties. Moreover, certain polyphenol combinations exhibit synergistic effects when delivered together - the combined polyphenols have a higher biological activity than the sum of the individual ones. However, the commercial application of polyphenols as nutraceuticals is currently limited because of their poor solubility characteristics; instability when exposed to light, heat, and alkaline conditions; and, low and inconsistent oral bioavailability. Colloidal delivery systems are being developed to overcome these challenges. In this article, we review the design, fabrication, and utilization of food-grade biopolymer-based delivery systems for the encapsulation of one or more polyphenols. In particular, we focus on the creation of delivery systems constructed from edible proteins and polysaccharides. The optimization of biopolymer-based delivery systems may lead to the development of innovative polyphenol-enriched functional foods that can improve human health and wellbeing.

Recent advances in flavonoid-grafted polysaccharides: Synthesis, structural characterization, bioactivities and potential applications

Plant derived flavonoids have been demonstrated to possess many valuable biological functions. In recent years, flavonoids have been successfully conjugated with polysaccharides through different graft copolymerization methods including chemical coupling, enzyme catalysis, free radical mediated grafting, and acid catalyzed condensation reactions. The successful grafting of flavonoids onto polysaccharides can be confirmed by several instrumental methods. The conjugation of flavonoids can significantly improve the antioxidant, antimicrobial, antitumor, hepatoprotective and enzyme inhibition properties of polysaccharides. Moreover, the applications of polysaccharides in food and pharmaceutical industries can be greatly broadened by grafting with flavonoids. Flavonoid-grafted polysaccharides can be developed as films for active packaging, hydrogels for controlled drug release, micelles for oral drug delivery, and emulsions for nutraceutical delivery. In general, the bioactivities and applications of conjugates are closely related to the type of flavonoid grafted, the grafting method used as well as the grafting efficiency. Recent advances in the synthesis, structural characterization, bioactivities and potential applications of flavonoid-grafted polysaccharides are summarized in this review.

Novel moisture-preserving derivatives of hyaluronan resistant to hyaluronidase and protective to UV light

Current studies have revealed the excellent moisture absorption-retention capacity of hyaluronan (HA); however, HA is easily degraded by hyaluronidase on the surface of skin. So, it is very necessary to develop an alternative derivative with low cytotoxicity and resistance to hyaluronidase. Herein, a HA decorated with photocaged groups was synthesized. The moisture absorption-retention capacity and hyaluronidase resistance of photocaged HA (HA-DMNB) and products of HA-DMNB irradiated by ultraviolet for different time (IHA-DMNB), were investigated. Results show that HA-DMNB is more resistant to hyaluronidase than HA, and HA-DMNB could release free carboxyl groups of HA upon ultraviolet to bond with H₂O. More importantly, HA-DMNB was protective against UV light. In addition, HA-DMNB and IHA-DMNB were observed to be nontoxic to HaCat cells. This study indicates that HA-DMNB may be effectively used as a moisture-preserving reagent.

Targeted intracellular protein delivery based on hyaluronic acid-green tea catechin nanogels

A novel ternary nanogel based on the self-assembly of hyaluronic acid-epigallocatechin gallate conjugates (HA-EGCG), linear polyethylenimine (PEI) and Granzyme B (GzmB) in an aqueous environment was developed for the targeted intracellular delivery of GzmB into cancer cells. Lysozyme-encapsulated HA-EGCG nanogels were first prepared and characterized. HA-EGCG nanogels exhibited smaller particle sizes and a more homogeneous size distribution than the HA counterpart. Fluorescence quenching and lysozyme activity studies revealed that EGCG moieties facilitated protein binding through physical interactions and led to the formation of stable nanogels. When CD44-overexpressing HCT-116 colon cancer cells were treated with GzmB-encapsulated HA-EGCG nanogels in vitro, a significant cytotoxic effect was observed. Caspase assays and intracellular trafficking studies confirmed that cell death was due to apoptosis triggered by the delivery of GzmB to the cytosol of those cells. In comparison, little cytotoxic effect was observed in CD44-deficient cells treated with GzmB-encapsulated HA-EGCG nanogels. This study highlights the potential utility of HA-EGCG as effective intracellular protein carriers for targeted cancer therapy.

STATEMENT OF SIGNIFICANCE

Intracellularly activated cytotoxic proteins can be used to kill cancer cells but viable carriers for such proteins are lacking. In this work, we developed novel nanogels based on selfassembly of hyaluronic acid (HA)-(-)-epigallocatechin-3-gallate (EGCG) conjugates, linear polyethylenemine (PEI) and the cytotoxic protein Granzyme B (GzmB) for the intracellular delivery of GzmB for cancer therapy. HA was exploited for its ability to target CD44 which are overexpressed in many types of cancer cells, while EGCG, the main component of green tea catechins, was chosen for its ability to bind to proteins. Characterization studies showed that EGCG facilitated protein complexation through physical interactions and led to the formation of stable nanogels. HA-EGCG nanogels were able to achieve CD44 targeted killing of HCT-116 cancer cells by delivering GzmB into the cytosol of these cells. We believe that the applications of the HA-EGCG nanogels can be expanded to the intracellular delivery of other cytotoxic protein drugs for cancer therapy.

Self-assembled ternary complexes stabilized with hyaluronic acid-green tea catechin conjugates for targeted gene delivery

Nanosized polyelectrolyte complexes are attractive delivery vehicles for the transfer of therapeutic genes to diseased cells. Here we report the application of self-assembled ternary complexes constructed with plasmid DNA, branched polyethylenimine and hyaluronic acid-green tea catechin conjugates for targeted gene delivery. These conjugates not only stabilize plasmid DNA/polyethylenimine complexes via the strong DNA-binding affinity of green tea catechin, but also facilitate their transport into CD44-overexpressing cells via receptor-mediated endocytosis. The hydrodynamic size, surface charge and physical stability of the complexes are characterized. We demonstrate that the stabilized ternary complexes display enhanced resistance to nuclease attack and polyanion-induced dissociation. Moreover, the ternary complexes can efficiently transfect the difficult-to-transfect HCT-116 colon cancer cell line even in serum-supplemented media due to their enhanced stability and CD44-targeting ability. Confocal microscopic analysis demonstrates that the stabilized ternary complexes are able to promote the nuclear transport of plasmid DNA more effectively than binary complexes and hyaluronic acid-coated ternary complexes. The present study suggests that the ternary complexes stabilized with hyaluronic acid-green tea catechin conjugates can be widely utilized for CD44-targeted delivery of nucleic acid-based therapeutics.